.red{
    color: red;
}
.blue{
    color: blue;
}

.out{
    width: 400px;
    height: 300px;
    background: #ddd;
    position: relative;
}
.nav{
    width: 100px;
    position: absolute;
    top:0;
    left: 0;
}
.content{
    width: 100%;
    padding-left: 100px;
    overflow-y: scroll;
    box-sizing: border-box;
    height: 300px;

}

/* 弹层样式 */
.black{
    width: 100vw;
    height: 100vh;
    background: rgba(0,0,0,0.5);
    position: fixed;
    top:0;
}
.ctx{
    position: absolute;
    left: 0;
    right: 0;
    top:100px;
    background: #fff;
    width: 300px;
    height: 200px;
    margin: auto;
}
.orange{
    width: 100px;
    line-height: 30px;
    height: 30px;
    text-align: center;
    background-color: orange;
    color: #fff;
    display: block;
}